Dave McCracken <dmccr@us.ibm.com> wrote:>> > --On Wednesday, April 02, 2003 17:58:08 -0600 Dave McCracken> <dmccr@us.ibm.com> wrote:> > > It's looking more and more like we should use your other suggestion. It's> > definitely simpler if we can make it failsafe. I'll code it up tomorrow.> > I thought of a big hole in the simpler scheme you suggested. It occurred> to me that try_to_unmap will fail. It will see the PageAnon flag so it'll> just walk the pte_chain and assume it doesn't have to walk the vmas. This> will leave the page with some stranded mappings. Actually> page_convert_anon will then finish, and we'll have a page where> try_to_unmap claims it has succeeded but still has mappings.>

Lock the page, and page reclaim will not go near it. It needs to be lockedacross page_convert_anon() anyway, to protect ->mapping.